Adhesive-Less DC Bus System and Method for Manufacturing

ABSTRACT

A system and method for manufacturing a power bus assembly is provided. The power bus assembly includes a first conductive sheet configured to receive a positive charge and distribute the positive charge to a plurality of connection points formed thereon. The power bus assembly also includes a second conductive sheet configured to receive a negative charge and distribute the negative charge to a plurality of connection points formed thereon. Additionally, the power bus assembly includes an insulating sheet arranged between the first conductive sheet and the second conductive sheet to electrically isolate the first conductive sheet from the second conductive sheet. A plurality of vice fasteners are included to secure the first conductive sheet, the second conductive sheet, and the insulating sheet together to form the power bus assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The present invention relates generally to power bus systems and, moreparticularly, to a bus assembly for DC bus links used in motor driveunits and the like that can be assembled using a plurality of clampingfasteners. The clamping fasteners are designed to secure the multiplelayers of the DC bus together without the need for adhesives.

Often, power delivered from a power source or supply is not properlyconditioned for consumption. For example, power plants are linked topower consuming facilities (e.g., buildings, factories, etc.) viautility grids that are designed to be extremely efficient at deliveringmassive amounts of power. To facilitate efficient distribution, power isdelivered over long distances as fixed frequency three-phase alternatingcurrent (AC) power. Similarly, in modern vehicle systems, especiallyhybrid vehicle systems, power management and storage systems handlepower in various forms, such as those that are desirable for storage andthose that are desirable for consumption. In either case, the power musttypically be converted or “conditioned” prior to consumption.

For example, motors and their associated loads are one type of commoninductive load employed at many consuming facilities that require powerconditioning. When a motor is the consuming point, power “conditioning”systems are utilized to convert the fixed frequency AC power deliveredover utility grids to a form suitable for driving the motor. To thisend, power conditioning for motor systems typically include AC-to-DC(direct current) rectifiers that convert the utility AC power to DCpower applied to positive and negative DC buses (i.e. across a DC link).The power distributed across the DC buses is then converted, for exampleby use of an inverter, to AC power designed to drive the motor.

Though the above-described system was described with respect to powerconditioning for motor systems, such DC bus systems are utilized in awide range of systems and applications. That is, regardless of theparticulars of the consuming components or ultimate application withinwhich the DC bus is employed, DC bus assemblies are often utilized todistribute DC power across various components for reconditioning,storage, and/or consumption.

To create a DC bus assembly, a variety of laminates or adhesively boundcomponents are utilized. For example, a first sheet of copper or similarconductor is arranged as the negative bus line. A second sheet of copperor other conductor is then arranged over the negative bus line andseparated by an insulator to serve as the positive bus line. Additionallayers that are separated by insulation layers may then be arranged overor between the positive and negative bus layers.

In most applications, the DC bus assembly must be structurally sound sothat various components can be securely mounted to the DC bus assembly.That is, each layer in the DC bus assembly must be joined to form acomposite structure capable of at least partially supporting componentsmounted to the assembly. Furthermore, the DC bus assembly must meetvarious environmental and operational tolerances, such as vibration andheat tolerances. For example, in the above-described example of a motordrive system, typically, the DC bus must have sufficient structuralintegrity to support both the rectifier and the inverter, as well asvarious additional components, such as capacitors, water coolingsystems, and the like. Furthermore, the DC bus must be able to sustainits structural integrity when subjected to vibrations and hightemperatures often associated with motor systems.

To create a DC bus assembly that is suitable for the desired application(i.e. has suitable structural integrity and meets the vibration andtemperature constraints), the layers (conductors and insulators) aretypically bonded together using adhesives. That is, each conductivelayer is bonded to each adjacent insulating layer, such that theassembly is formed by alternating layers of conductor and insulator thatare all bonded through adhesives. These laminated DC bus structuresprovide noise cancellation properties and have become commonplace inpower conversion equipment.

While such manufacturing methods have long been employed to greatsuccess with meeting the structural requirements needed to withstandvibrations and temperature changes associated with a wide variety ofenvironments, they are rather costly. In particular, the process ofaligning and gluing the individual layers requires a high degree ofskill because the manufacturer must carefully align the adjacent layersto ensure that adjacent conductors; will not be in contact and will notlater move into contact when the separating insulator is subjected toheat and vibration.

As such, the cost of more complex bus structures is often prohibitive.For example, a “3D” bus structure, where the bus sheets are bent toextend into multiple planes, is often cost prohibitive because theprocess of correctly aligning and gluing adjacent layers simultaneouslyacross multiple planes is extremely difficult, if not impossible.Therefore, though such a 3D bus structure could be advantageouslyutilized in a wide variety of systems since it would permit the size andshape of the bus to be more compact and/or adapted to fit intoinon-traditional environments, it is generally foregone in favor of thetraditional flat or planar bus design due to cost and quality controlconstraints.

Therefore, it would be desirable to have a system and method forcreating Et power bus assembly that reduces manufacturing costs andcomplexities, is more adaptable to various bus designs, and providesincreased structural integrity.

BRIEF SUMMARY OF THE INVENTION

The present invention overcomes the aforementioned drawbacks byproviding a system and method for creating a power bus that utilizes aplurality of clamping fasteners designed to secure the multiple layersof the power bus together without the need for adhesives.

In accordance with one aspect of the present invention, a power busassembly is disclosed that includes a first conductive sheet configuredto receive a positive charge and distribute the positive charge to aplurality of connection points formed thereon. The power bus assemblyalso includes a second conductive sheet configured to receive a negativecharge and distribute the negative charge to a plurality of connectionpoints formed thereon. Additionally, the power bus assembly includes aninsulating sheet arranged between the first conductive sheet and thesecond conductive sheet to electrically isolate the first conductivesheet from the second conductive sheet. A plurality of vice fastenersare included to secure the first conductive sheet, the second conductivesheet, and the insulating sheet together to form the power bus assembly.

In accordance with another aspect of the present invention, a power busassembly is disclosed that includes a first conductive sheet having aplurality of connection points and a plurality of through holes formedtherein. The first conductive sheet is configured to receive a positivecharge and distribute the positive charge to the plurality of connectionpoints. The power bus assembly also includes a second conductive sheethaving a plurality of connection points and a plurality of through holesformed therein. The second conductive sheet is configured to receive anegative charge and distribute the negative charge to the plurality ofconnection points. An insulating sheet is arranged between the firstconductive sheet and the second conductive sheet to electrically isolatethe first conductive sheet from the second conductive sheet. Theinsulating sheet also has a plurality of through holes arranged thereinthat are designed to align with the through holes formed in the firstconductive sheet and the second conductive sheet to form a plurality ofthrough hole sets that extend through the first conductive sheet, thesecond conductive sheet, and the insulating sheet. Additionally, thepower bus assembly includes a plurality of coupling fasteners. Eachcoupling fastener is aligned to extend through a through hole set andsecure the first conductive sheet, the second conductive sheet, and theinsulating sheet together to form the power bus assembly.

In accordance with yet another aspect of the invention, a method ofmanufacturing a power bus assembly is disclosed that includes forming afirst conductive sheet configured to receive a positive charge anddistribute the positive charge to a plurality of connection pointsarranged thereon. The method also includes forming a second conductivesheet configured to receive a negative charge and distribute thenegative charge to a plurality of connection points arranged thereon.Also, the method includes forming an insulating sheet having a perimetersubstantially matched to perimeters of the first conductive sheet andthe second conductive sheet and cutting a plurality of through holes inthe first conductive sheet, the second conductive sheet, and theinsulating sheet. The method further includes arranging the insulatingsheet between the first conductive sheet and the second conductive sheetto form a power bus assembly with the through holes formed in the firstconductive sheet, the second conductive sheet, and the insulating sheetaligned to form a plurality of passages through the power bus assembly.Furthermore, the method includes affixing a clamping fastener withineach of the plurality of passages to secure the first conductive sheet,the second conductive sheet, and the insulating sheet together in thepower bus assembly.

In accordance with still another aspect of the invention, a clampingfastener for creating an adhesive-less power bus assembly is disclosedthat includes a first clamping plate configured to be arranged within athrough hole formed in a power bus assembly and a flange axially offsetfrom the first clamping plate and extending radially from the firstclamping plate to extend over a portion of a first side of the power busassembly. The clamping fastener also includes a second clamping plateconfigured to be arranged within the through hole in the power busassembly and a flange axially offset from the second clamping plate andextending radially from the second clamping plate to extend over aportion of a second side of the power bus assembly arranged opposite thefirst side of the power bus assembly. A hub extends from the secondclamping plate toward the first clamping plate through the through holein the power bus assembly and a connector extends through the hub toengage the first clamping plate and the second clamping plate andcompress the first side and the second side of the power bus assemblytogether.

Various other features of the present invention will be made apparentfrom the following detailed description and the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will hereafter be described with reference to theaccompanying drawings, wherein like reference numerals denote likeelements, and:

FIG. 1 is a schematic representation of a motor system including a powerconditioning device in accordance with the present invention;

FIG. 2 is a perspective view of a power bus arranged in a planarconfiguration assembled using clamping fasteners in accordance with thepresent invention;

FIG. 3 is an exploded view of the power bus of FIG. 2;

FIG. 4 is a cross-sectional view of a clamping fastener engaged with thepower bus of FIG. 2;

FIG. 5 is a perspective view of a first clamping plate of the clampingfastener included in FIGS. 2-4;

FIG. 6 is a plan view of a second clamping plate of the clampingfastener included in FIGS. 2-4; and

FIG. 7 is a perspective view of a multi-planar power bus assembled usingthe clamping fasteners of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the following description is directed a motor drive system 10, itis contemplated that the following power bus system can be used with awide variety of associated systems. For example, it is contemplated thatthe power bus may be used with vehicular power systems, such as hybridvehicle systems.

Referring now to FIG. 1, the present invention can be described in thecontext of a motor control system 10. The motor control system 10includes a power supply 12 and a motor drive unit 14. The power supply12 provides power to the motor drive unit 14 that, in turn, converts thepower to a more usable form for a three-phase motor 16 that drives anassociated load 18.

The motor drive unit 14 includes a variety of components, such as arectifier 20, an inverter 22, and a controller 24, each of which areconnected to a power bus 25. During operation, the power supply 12provides three-phase AC power, for example, as received from a utilitygrid over transmission power lines 26. However, it is also contemplatedthat the power supply 12 may be designed to deliver single-phase power.In either case, the nominal line voltage delivered by the power supply12 is dependent on the particulars of the motor 16, load 18, and poweravailable to the power supply 12 to drive the motor drive 14. Forexample, the power supply 12 may be a transmission power receptacle, inwhich case, the power available to the motor control system 10 will bedependent upon the specifics of the geographic region in which the motorcontrol system 10 is located (e.g. 50 Hz/60 Hz or 220 V/380V).

Accordingly, the rectifier 20 is designed to receive AC power from thepower supply 12 and convert the AC power to DC power that is deliveredto the power bus 25. Continuing with the example of a motor drive system10, the inverter 22 is positioned between positive and negative DC buses28, 30 of the power bus 25. As is well known in the motor control arts,the inverter 22 includes a plurality of switching devices (e.g., BJTsand the like) that are positioned between the positive and negativebuses 28, 30 of the power bus 25 and output supply lines 32 of theinverter 22, such that the controller 24 can open and close specificcombinations of the switches to sequentially generate positive andnegative DC voltage pulses on each of the supply lines 32. By openingand closing the switches of the inverter 22 in specific sequences, themotor drive unit 14 generates AC power having controllable amplitudesand frequencies on each of the supply lines 32. By providing knownsequences of AC power across the motor windings, the motor 16 is drivento turn a drive shaft 34 that, in turn, drives the load 18.

Referring now to FIGS. 2 and 3, one arrangement for the power bus 25 isshown in detail. In particular, the power bus 25 is arranged in a planarbus structure. The power bus 25 is a multi-layer structure that includesat least a first conductive sheet 36, for example, designed to carry apositive charge and a second conductive sheet 38, for example, designedto carry a negative charge. Separating the first conductive sheet 36 andthe second conductive sheet 38 is an insulating sheet 40.

In addition to the conductive sheets 36, 38 and the insulating sheet 40,a cover sheet 42 may be included that is separated from adjacentconductors 36, 38 by an associated insulating sheet 44. Additionally,the cover sheet 42 may be designed to be grounded so as to form anelectromagnetic shield over the power bus 25. Finally, it iscontemplated that one or more serial connection layers 46 may beincluded that provide connection points to non-adjacent conductor layersand that are separated from adjacent conductive layers by an associatedinsulating layer 48.

When these layers 40-48 are arranged together, the power bus 25 presentsa plurality of connection points for delivering or receiving power fromthe power bus 25. For example, connection points may be provided such asstuds 50 or receptacles 52. In this regard, the studs 50 may be used asconnection points for large devices, such as the rectifier 20 andinverter 22 of FIG. 1. On the other hand, the receptacles 52 may be usedas connection points for other devices, such as filtering capacitors inthe case of a motor drive (FIG. 1) or storage capacitors in the case ofother systems, such as hybrid vehicle systems.

In any case, the cover sheet 42 may be included to fortify thestructural integrity of the assembled power bus 25. Accordingly, thepower bus 25 can be designed to support an increased percentage of theweight of a device mounted thereto, such as a rectifier or inverter.Furthermore, the cover sheet 42 may be designed to increase thestructural integrity of the power bus 25 so that it is capable ofsupporting devices or withstanding influences that would otherwisedamage the power bus 25.

To secure the layers 40-48 together and within the proper alignments, aplurality of clamping fasteners 54 are included. In particular, theclamping fasteners 54 are designed to be positioned within holes 56formed in each layer 40-48 that form coaxially aligned passages throughthe power bus 25 when the layers 40-48 are properly assembled.

Referring now to FIGS. 4-6, the clamping fasteners 54 include a firstclamping plate 58 and a second clamping plate 60. Each clamping plate56, 60 includes a flange 62 axially offset from each clamping plate 58,60 and extending radially from each clamping plate 58, 60 to extend overa portion of the power bus assembly 25.

A hub 64 extends from the second clamping plate 60 toward the firstclamping plate 58 through the through hole 56 in the power bus assembly25. An annular notch 66 formed opposite the flange receives an end ofthe hub 54 opposite the second clamping plate 60 to restrict movement ofthe first clamping plate 58 with respect to the second clamping plate60.

The clamping plates 58, 60 include holes 68, 70 that are designed to bealigned coaxially with the holes 56 in the power bus 25. Accordingly, apassage is formed through the first clamping plate 58, the hub 64, andthe second clamping plate 60. A connector, in the form of a threadedscrew 72, is designed to pass through the hole 68 in the first clampingplate 58 to engage the hub 64. It is contemplated that the hub 64includes a narrowed interior periphery 74 (i.e., having a reduceddiameter) that is engaged by the screw 72. Accordingly, when the screw72 is passed through the hole 68 in the first clamping plate 58 toengage the hub 64, the threads of the screw 72 engage the narrowedinterior periphery 74 of the hub 64. For example, it is contemplatedthat the screw 72 may be a Plastite screw. Plastite is a registeredtrademark of Research Engineering & Manufacturing, Inc. Corporation ofNew Bedford, Mass.

In any case, the screw 72 is designed to pull the first clamping plate58 toward the second clamping plate 60 as the screw 72 is tightened tosecure the layers 40-48 of the power bus 25 together without the needfor adhesives, glues, or the like. Furthermore, the engagement of thescrew 72 with the narrowed interior periphery 74 of the hub 64 isdesigned to secure the screw 72 against the potential for the screw 72to loosening due to vibrations that may be experienced during operation.To aid in the process of threading the screw 72 through the hub 64 andinto the second clamping plate 60, as shown in FIG. 6, it iscontemplated that the flange 62 extending from the second clamping plate60 may include notches designed to aid in fixing the position of thesecond clamping plate 60 (i.e., hold against rotation) as the screw 72is threaded through the passage 70. Also, as illustrated in FIG. 6, itis contemplated that the hub 64 may extend beyond the second clampingplate toward the flange 62 to provide an additional extent through whichthe screw 72 can extend.

Additionally, it is preferable that at least the first clamping plate58, the second clamping plate 60, and the hub 64 are formed of anon-conductive material. In accordance with one aspect of the invention,it is contemplated that the first clamping plate 58, the second clampingplate 60, and the hub 64 may be formed of a variety of plastic, rubber,or other non-conductive materials. For example, in accordance with oneembodiment, the clamping fasteners 54 (with the exception of the screw)may be formed of Mindel B-430. Mindel is a registered trademark of UnionCarbide Corporation New York of Danbury Conn.

Referring now to FIG. 7, by utilizing the above-described clampingfasteners 54, it is possible to create power bus systems 80 that extendin multiple planes. That is, while a power bus 80 that includes portionsextending beyond a single plane would be cost prohibitive to manufactureefficiently using adhesives, using the clamping fastners 54 of thepresent invention, such bus architectures are affordable. For example,such bus designs can be cut by common metal fabrication facilities, asopposed to a manufacturer specializing in bus design, and then assembledusing the clamping fasteners 54 of the present invention, without theneed for the highly skilled assembly processes of specialized busmanufacturers. Accordingly, a power bus may be designed to havevirtually any geometry without substantial increases in manufacturingcosts.

Therefore, the present invention provides a system and method forcreating a power bus that reduces manufacturing costs and complexities,is more adaptable to various bus designs, and provides increasedstructural integrity. In particular, the present invention provides asystem and method for creating a power bus that utilizes a plurality ofclamping fasteners designed to secure the multiple layers of the powerbus together without the need for adhesives. The clamping fasteners areself-fixing so minimal manufacturing skill is required to assemble agiven power bus.

Additionally, the clamping fasteners are specifically designed towithstand the heating and vibrations often associated with theoperational environments of many power busses. Accordingly, the presentinvention provides a significant improvement over traditional power busassembly systems that rely on adhesives, which are known to besusceptible to such environmental influences over time.

The present invention has been described in terms of the variousembodiments, and it should be appreciated that many equivalents,alternatives, variations, and modifications, aside from those expresslystated, are possible and within the scope of the invention. Therefore,the invention should not be limited to a particular describedembodiment.

1. A power bus assembly comprising: a first conductive sheet having aplurality of connection points and configured to receive a positivecharge and distribute the positive charge to the plurality of connectionpoints; a second conductive sheet having a plurality of connectionpoints and configured to receive a negative charge and distribute thenegative charge to the plurality of connection points; an insulatingsheet arranged between the first conductive sheet and the secondconductive sheet to electrically isolate the first conductive sheet fromthe second conductive sheet; and a plurality of vice fasteners securingthe first conductive sheet, the second conductive sheet, and theinsulating sheet together to form a power bus assembly.
 2. The power busassembly of claim 1 further comprising a plurality of holes formed inthe first conductive sheet, the second conductive sheet, and theinsulating sheet that are coaxially aligned to form through holesarranged in the power bus assembly.
 3. The power bus assembly of claim 2wherein each vice fastener includes: a first clamping plate arrangedwithin one of the through holes formed in the power bus assembly andincluding a flange axially offset from the first clamping plate andextending radially from the first clamping plate to extend over aportion of a first side of the power bus assembly proximate to the firstconductive sheet; a second clamping plate arranged within the one of thethrough holes formed in the power bus assembly and including a flangeaxially offset from the second clamping plate and extending radiallyfrom the second clamping plate to extend over a portion of a second sideof the power bus assembly proximate to the second conductive sheet; ahub extending from the second clamping plate toward the first clampingplate through the one of the through holes formed in the power busassembly; and a connector extending through the hub to engage the firstclamping plate and the second clamping plate and compress the first sideand the second side of the power bus assembly together.
 4. The power busassembly of claim 3 wherein the first clamping plate, the secondclamping plate and the hub are formed of a non-conductive material. 5.The power bus assembly of claim 1 wherein the first clamping plateincludes an annular notch formed opposite the flange to receive an endof the hub opposite the second clamping plate to restrict movement ofthe first clamping plate with respect to the second clamping plate. 6.The power bus assembly of claim 1 wherein the connector includes athreaded shaft configured to pass through a hole formed in the firstclamping plate and aligned coaxially with the through hole in the powerbus to engage the hub extending from the second clamping plate towardthe first clamping plate.
 7. The power bus assembly of claim 1 furthercomprising a plurality of conductive sheets and insulating sheetsextending away from a plane formed by the first conductive sheet and thesecond conductive sheet to form a power bus assembly extending inmultiple planes, wherein each plane of the power bus assembly includes aplurality of vice connectors compressing the plane together.
 8. Thepower bus assembly of claim 1 further comprising a third conductivesheet forming a serial layer extending over at least a portion of atleast one of the first conductive sheet and the second conductive sheetand at least partially separated from the first conductive sheet and thesecond conductive sheet by another insulating sheet having holes formedtherein to provide electrical connections to one of the first conductivesheet and the second conductive sheet about the connection points. 9.The power bus assembly of claim 1 further comprising at least two inputmounting studs and two output mounting studs extending from the firstconductive sheet and the second conductive sheet configured to receive arectifier and an inverter.
 10. The power bus assembly of claim 9 furthercomprising a cover layer extending over at least one of the firstconductive sheet and the second conductive sheet and held thereto by theplurality of vice fasteners to fortify the power bus assembly to supportthe rectifier and the inverter thereon when mounted to the inputmounting studs and the output mounting studs.
 11. The power bus assemblyof claim 10 wherein the cover layer includes a grounding tab configuredto ground the cover layer to form an electromagnetic shield over thepower bus assembly.
 12. The power bus assembly of claim 10 wherein thepower bus assembly forms a DC bus link configured to receive DC powerfrom the rectifier and deliver the DC power to the inverter to conditionthe DC power for delivery to a motor.
 13. A power bus assemblycomprising: a first conductive sheet having a plurality of connectionpoints and a plurality of through holes formed therein, the firstconductive sheet configured to receive a positive charge and distributethe positive charge to the plurality of connection points; a secondconductive sheet having a plurality of connection points and a pluralityof through holes formed therein, the second conductive sheet configuredto receive a negative charge and distribute the negative charge to theplurality of connection points; an insulating sheet arranged between thefirst conductive sheet and the second conductive sheet to electricallyisolate the first conductive sheet from the second conductive sheet andhaving a plurality of through holes arranged therein to align with thethrough holes formed in the first conductive sheet and the secondconductive sheet to form a plurality of through hole sets that extendthrough the first conductive sheet, the second conductive sheet, and theinsulating sheet; and a plurality of coupling fasteners, each couplingfastener aligned to extend through a through hole set and secure thefirst conductive sheet, the second conductive sheet, and the insulatingsheet together to form a power bus assembly.
 14. The power bus assemblyof claim 13 wherein each coupling fastener includes: a first clampingplate arranged within one end of the hole set formed in the power busassembly and including a flange axially offset from the first clampingplate and extending radially from the first clamping plate to extendover a portion of a first side of the power bus assembly proximate tothe first conductive sheet; a second clamping plate arranged withinanother end of the hole set formed in the power bus assembly andincluding a flange axially offset from the second clamping plate andextending radially from the second clamping plate to extend over aportion of a second side of the power bus assembly proximate to thesecond conductive sheet; a hub extending from the second clamping platetoward the first clamping plate through the hole set formed in the powerbus assembly; and a connector extending through the hub to engage thefirst clamping plate and the second clamping plate and compress thefirst side and the second side of the power bus assembly together. 15.The power bus assembly of claim 13 wherein the connector includes athreaded shaft configured to pass through a passage formed in the firstclamping plate and aligned coaxially with the hole set in the power busassembly to engage the hub extending from the second clamping platetoward the first clamping plate.
 16. The power bus assembly of claim 15wherein the hub includes a passage aligned coaxially with the throughhole set and the passage formed in the first clamping plate and whereina diameter of the passage is less than a diameter of the threaded shaftand, wherein that the threaded shaft is caused to bore into the hub asthe threaded shaft is extended through the passage extendingtherethrough.
 17. A method of manufacturing a power bus assemblycomprising: forming a first conductive sheet configured to receive apositive charge and distribute the positive charge to a plurality ofconnection points arranged thereon; forming a second conductive sheetconfigured to receive a negative charge and distribute the negativecharge to a plurality of connection points arranged thereon; forming aninsulating sheet having a perimeter substantially matched to perimetersof the first conductive sheet and the second conductive sheet; cutting aplurality of through holes in the first conductive sheet, the secondconductive sheet, and the insulating sheet; arranging the insulatingsheet between the first conductive sheet and the second conductive sheetto form a power bus assembly with the through holes formed in the firstconductive sheet, the second conductive sheet, and the insulating sheetaligned to form a plurality of passages through the power bus assembly;and affixing a clamping fastener within each of the plurality ofpassages to secure the first conductive sheet, the second conductivesheet, and the insulating sheet together in the power bus assembly. 18.The method of claim 17 wherein the step of affixing the clampingfastener includes: arranging a first clamping plate within a throughhole such that a flange axially offset from the first clamping plateextends radially from the first clamping plate over a portion of thefirst conductive sheet surrounding the through hole; arranging a secondclamping plate within the through hole such that a flange axially offsetfrom the second clamping plate extends radially from the second clampingplate over a portion of the second conductive sheet surrounding thethrough hole; engaging a hub extending from the second clamping platetoward the first clamping plate through the through hole within a notchformed in the first clamping plate; and extending a connector throughthe hub to engage the first clamping plate and the second clamping plateand compress the first conductive sheet, the second conductive sheet,and the insulating sheet together in the power bus assembly.
 19. Themethod of claim 18 wherein the step of extending the connector throughthe hub includes screwing a threaded shaft through a hole formed in thefirst clamping plate into an un-threaded passage formed in the hub toengage a head formed at one end of the threaded shaft with the firstclamping plate.
 20. A clamping fastener for creating an adhesive-lesspower bus assembly comprising: a first clamping plate configured to bearranged within a through hole formed in a power bus assembly andincluding a flange axially offset from the first clamping plate andextending radially from the first clamping plate to extend over aportion of a first side of the power bus assembly; a second clampingplate configured to be arranged within the through hole in the power busassembly and including a flange axially offset from the second clampingplate and extending radially from the second clamping plate to extendover a portion of a second side of the power bus assembly arrangedopposite the first side of the power bus assembly; a hub extending fromthe second clamping plate toward the first clamping plate through thethrough hole in the power bus assembly; and a connector extendingthrough the hub to engage the first clamping plate and the secondclamping plate and compress the first side and the second side of thepower bus assembly together.
 21. The clamping fastener of claim 20wherein the first clamping plate includes an annular notch formedopposite the flange to receive an end of the hub opposite the secondclamping plate to restrict movement of the first clamping plate withrespect to the second clamping plate.
 22. The clamping fastener of claim1 wherein the connector includes a threaded shaft configured to passthrough a hole formed in the first clamping plate and aligned coaxiallywith the through hole in the power bus assembly to engage the hubextending from the second clamping plate toward the first clampingplate.
 23. The clamping fastener of claim 22 wherein the hub includes ahole aligned colaxially with the through hole and the hole formed in thefirst clamping plate and wherein a diameter of the hole is less than adiameter of the threaded shaft, such that the threaded shaft is causedto bore into the hub as the threaded shaft is extended through the hub.24. The clamping fastener of claim 22 wherein the first clamping plate,the second clamping plate, and the hub are formed of a non-conductivematerial.